Is it permissible for a girl to refuse to complete her university education because men teach her, and would she be sinful if her family forced her to do so?

A man teaching a woman is not inherently forbidden. It is permissible if there is no forbidden khalwa (private seclusion) or ikhtilat (unrestricted intermingling), and if fitna (temptation) is safeguarded against. The girl must obey her parents in completing her studies. However, if studying is accompanied by clear forbidden acts, then it is not permissible for her to continue, unless she is coerced and fears harm, in which case the sin falls upon the one who coerced her. She must abandon the disobedience immediately once the coercion ceases.